Production of titanium hydride



Sept. 16, 1947. P. P. ALEXANDER PRODUCTION OF TITANIUM HYDRIDE FiledMarch 26, 1945 ATTORNEYS per'ature powdered titanium, which is separatedfrom the Patented Sept. 16, 1947 PRODUCTIOOF TITANIUM HYDRIDE' Peter P.Alexander, Beverly, Mass., asslgnor Metal Hydrides Incorporated,Beverly, Mass.,

a corporation of Massachusetts Application March 26, 1945, Serial No.504,855

l Claims. l

This invention relates to the production oi titanium hydride and has forits object certain improvements in the method of producing titaniumhydride.

While it is known that titanium hydride may beproduced by reactingmetallic titanium with hydrogengas'at an elevated temperature, theresulting product is generally impure because the metallic titaniumemployed as a starting material is generally impure. On account of itshigh `melting point,1800 C., its great tendency to combine with oxygen,nitrogen and carbon at high temperatures and the readiness with which itforms alloys with the common metals, the production of metallic titaniumin a state of purity is very difllcult. Various proposals have beenadvanced to produce titanium pyrometallurgically. For example,tluotitanates have been a small bomb capable of withholding a totalinternal pressure of 80,000 lbs. and then to heat the bomb to lowredness. The resulting reaction takes place with explosive violence. Theresidue obtainedafter cooling and washing consists for the most'part ofmelted titanium but thereare also present some coarse and semi-moltenpow- `der and a little ne powder. The yield is about 90% `of vthattheoretically obtainable, the loss 'being attributable to oxidation. Alater procedure is to react titanium tetrachloride with magnesium in amolybdenum-lined crucible in the presence of an inert gas at an elevatedtem- 'I'he reaction results in an impure resulting magnesium chloride.These methods of producingmetalllc titanium obviouslyV leave a greatdeal to be desired. v

As a result of my investigations, I4 have dis- A'covered that titaniumhydride may be produced readilyl and `efllciently byj an'improvedpyrometali .lurgical method. When operating in the special pound toeiecta sulzist'ai'itially complete reduction; leavinga 'metallictitanium product o'f high purity which may be Aconverted promptlyV intotitanium hydride of 'high purity.

` Inaccordance 1with the invention, a charge of metal hydride isgradually heated in a reduction zone to a temperature suiliciently highto dissociate the alkaline `,earth metal hydride into alkaline earthmetal and hydrogen gas and to reduce the titanium compound with thealkaline earth4 metal thus released to form metallic ti tanium and acompound of the alkaline earth metal. The reaction zone is evacuatedwhile at a temperature sulclently high to dissociate the excess alkalineearth metal hydride to remove hydrogen gas therefrom and to distill andpass the excess alkaline earth metal thus released from the charge intoa body of absorbing material. Hydrogen gas is then admitted to theheated reaction zone in amount suilicient to convert the reducedtitanium to titanium hydride. The resulting charge containing thetitanium hydride and compound of the alkaline earth metal is cooled,after which the titanium hydride is separately recovered by leaching thecharge with a solvent for the compound of the alkaline earth metal.

Various titanium compounds, such as titanium dioxide, titanium chloride.titanium iodide, or other halogen compound of totanium, etc., may bethus treated to convert the available titanium into a form of highpurity which may then be converted into titanium hydride of high purity.In a presently preferred practice of the invention, titanium dioxidepigment is employed as the source of titanium.

Among the reducing agents particularly adapted for the practice of theinvention are the alka- .i The reaction zone is preferably evacuated inthe beginning to removeair. and moisture, and then filled with an inertgas. The inert gas` is advantageuslya monatomic'gas, such asargon `or`lhelium, or a mixture of suchgases, A` sumfcient amount of the lgas isfedyintdtheieduction zonektor'aise'its pressure toa poln at `which up-4ward movement of the vapors of reducing metal is inhibited, the'objectbeing to keepthe reducing 'metal jin contact with lthe titaniumcompound titanium compound zand excessv alkaline earth o l long ,enough'to' effect the desiredreaction,l and sorbing material may be removedfromthe chargev of titanium dioxide and reducing metal, it is zone and alayer of titanium dioxide pigment is placed on top of the charge. Thereduction zone is evacuated, preferably at an elevated temperaerablyunder positive pressure.

ture, to remove air and moisture; after which the reaction zone isfilled with helium or argon, pref- The charge is z gradually heateduntil-the 'calcium hydride dishighly advantageous to place it as a layeron top of the charge. In a presently preferred practice of theinvention, a layer of titanium dioxide pigment, similar to the titaniumdioxide pigment in the charge, of suitable thickness, is placed on topof the charge.

The charge of titanium dioxide pigment and excess alkaline earth metalhydride, with the layer of absorbing material, is heated in a reductionzone that has been advantageously evacuated to remove objectionable airand moisture, the air being replaced with a suitable inert gas, such ashelium or argon, preferably under'substantial I have` positive pressure,as pointed out above. found that a pressure of pounds is effective underthe conditions 'at present employed'in the practice of the invention.

As the charge gradually rises 'in temperature, the alkaline earth metalhydride gradually dissociates into hydrogen gas and alkaline earthmetal. The alkaline earth metal thus released promptly reacts with thetitanium dioxide pigment to form metallic titanium and an oxide of thealkaline earth metal. This reaction gradually progresses until thereduction goes to completion. The hydrogen-gas released by dissociationof the alkaline earth metal hydride contacts the reduced titaniumparticles and keeps their surfaces clean, for example, from surfaceoxide. The excess alkaline earth metal hydridetends to. remain as suchat this stage of the operation. The reaction zone is then evacuated,while at a temperature suiliciently high to dissociate the excessalkaline earth metal hydride to remove hydrogen gas, as well as othergaseous reaction products, such as steam, and to distill and pass theexcess alkaline earth metal thus released from the charge into the layerof absorbing material. If, for example, the absorbing material is alsotitanium dioxide, some of it may be reduced by the distilled excessreducing metal. Depending upon the temperature of the layer of absorbingmaterial,

some of the distilled excess reducing metal may' 'then admitted to theheated reaction zone in amount suilicient to convert the reducedtitanium to titanium hydride; the charge being cooled if lnecessary tothe hydriding temperature of the reduced titanium. The resulting chargecontaining -the hydrided titanium particles and oxide of the alkalineearth metal is cooled. The charge is then leached with' a solvent forthe alkaline earth metal oxide to recover the titanium hydride.

A charge of nely divided andintimately admixed titanium dioxide pigmentand excess calcium hydride, for example, is placed in a reactionsociates into calicum and hydrogen gas, and the reducing reaction setsin. The reactions may be indicated as follows: l

And'the combined dissociation and reducing reactions may be indicatedconveniently as follows:

Asa result, the calcium hydride is initially dissociated into calcium,the desired reducing metal, and hydrogen gas; the calcium reduces thetitanium dioxide to titanium and forms calcium oxide; and the hydrogengas released by dissociation of the calcium hydride reacts wth surfaceoxide on the reduced titanium particles to form moisture which ispromptly converted into steam.

The reaction zone lis then evacuated, While at a temperaturesuiliciently high to dissociate the excess calcium hydride, to removehydrogen gas as well as to dlstill and pass the excess calcium from thecharge into the absorbing layer of titanium dioxide in which some or allof it reduces some of the titanium dioxide and in which some of it maybe condensed. The layer of titanium dioxide should be sufflciently thickto cat ch and retain substantially all of the excess calciumV as itrises from the underlying charge.

Hydrogen gas is then passed into the heated reaction zone in amountsuillcient to convert the reduced titanium in the charge to titaniumhydride, the reaction for which may be indicated as follows:

I Since the reducing reaction, Equation 2 above,

in which the freshly released calcium reacts with the titanium dioxideto form calcium oxide'and titanium, takes place at a temperature higherthan that at which the hydriding reaction of Equation 4 can take place,the charge is cooled, if necessary, to the hydriding temperature.

Various procedures may then be employed to recover the titanium hydridein the main part of the charge. Thus, the resultant charge and top layerare permitted to cool, after which they are removed from the reactionzone.

There is a clear line of demarcation between the resultant charge andtop layer. The charge tends to be a sintered mass of calcium oxide andvtitanium hydride particles, whereas the absorbing layer of titaniumdioxide containing the excess distilled calcium tends to remain in afluffy condition and may be readily shaken oi or brushed away.

The resultant charge containing the calcium oxide and titanium hydridemay be treated in any suitable manner to separate the two. The calciumoxide may be removed by leaching the charge, preferably in crushed form.with a suittable solvent, for example dilute acid, such as hydrochloric,sulfuric, or acetic, or a solution of ammonium salt, in which it issoluble, but in which the titanium-.hydride is substantially insoluble.

These and other features of the invention will be better understood byreferring to the accomhaving attached thereto a vertical pipe I4 withlateral -valved branches I and I6 and vertical valvedrbranch I1connectible with a source of vacuum, inert gas, such as helium or argon,and hydrogen gas, respectively. A gasket I8 is disposed between thecover and the flanged top portion of the outer retort, the threeelements forming a non-leakable connection by means of a plurality ofspaced bolts I9. A removable inner retort 2li having an open top restswithin the outer retort.

The heating furnace consists essentially of a box-like chamber 2| havinga refractory bottom 22, side and end walls 23 and a top 24 with anopening of a size adapted to receive the outer retort. An expandingopening 25 is providedvat or near a lower corner of one of the sidewalls of the chamber, for the introduction of heating gases into thechamber. A flue opening 26 extends through another Wall, preferably at ahigher level, so that heating gases passed into the chamber throughopening 25 tend to pass around and in contact with the outer retortbefore leaving the chamber through the ue opening.

The apparatus may be used as follows: A charge of finely divided andintimately admixed titanium dioide pigment and excess calcium hydride,for example, is placed in the bottom of inner retort 2|). An absorbinglayer of titanium dioxide pigment is placed on the top of the charge,the layer being of suitable thickness and spread uniformly across theentire top of the charge. The inner retort is then placed in outerretort I0, gasket I8 is placed in position on the flanged portion of thetop of the outer retort, and removable cover I3 is securely boltedthereon to make a non-leaking joint.

With the valves in lateral branch I6 and vertical branch I'I closed, thevalve in lateral branch I5 is opened and the retorts are placed undervacuum to remove objectionable air and moisture. Heating gases arepassed through opening 26 into furnace chamber 2l. The retorts are keptunder vacuum preferably as the charge rises in temperature to facilitateremoval of the air and moisture. Before the charge reaches a temperatureat which the calcium hydride dissociates and reduction of the titaniumdioxide in the charge takes place, the valve in lateral branch I5 isclosed and that in lateral branch Ii is opened to illl the retorts withinert gas, for example helium, preferably under pressure, for example 15pounds. The introduction of heating gases into chamber 2| is continuedto raise the temperature of the charge to the point at whichdissociation of the calcium hydride and reduction of the titaniumdioxide in the charge take place. When the reduction has gone tocompletion, with the valve in lateral branch I6 closed. the valve inlateral branch I5 is opened `to evacuate the retorts. The temperature issumciently high to dissociate the excess calcium hydride in the chargeas evacuation takes place. As a result, hydrogen previously released andhydrogen released at this stage, the inert gas and gaseous products ofreaction are removed from the retorts. 'I'he excess calcium released isdistilled and passed from the charge into the absorbing layer oftitanium dioxide. where it reacts at least in part with some of thetitanium dioxide. If the temperature of the layer is suiiiciently low,some of the calcium may be condensed therein. In any event. the layer oftitanium dioxide should be sufciently deep to retain substantially allof the distilled excess calcium, either as such or as calcium oxide, sothat calcium does notcondenseon the upperpart of the inner or outerretort, on the cover or in the vertical pipe and lateral branches.

The valve in lateral branch I5 is closed; the valve in lateral branch I6is preferably opened to admit inert gas to the reaction zone, undersubstantial positive pressure; and the valve in vertical branch I1 isopened to admit enough hydrogen gas to convert the reduced titanium inthe charge to titanium hydride. As indicated above, ,fthe temperature ofthe charge may be dropped to that at which the desired hydridingreaction can take place.

The retorts and hence the resulting charge and absorbing layer arepermitted to cool. Cover I3 is removed; inner retort 20 is withdrawnfrom outer retort I0 and its contents are removed therefrom. A clearline of demarcation tends to exist between the resulting absorbing layerand the underlying charge. The absorbing layer of titaniumdioxidecontaining the distilled excess calcium remains essentially in a fluffycondition. 'Ihe underlying charge containing the titanium hydride andcalcium oxide is a more or less sintered coherent mass. It is thereforea simple matter to separate the two. The fluffy top layer may be brushedoff the underlying charge.

Since the top layer consists of titanium dioxide, the reduction `of someof it by the distilled excess calcium does not contaminate the initialreduced titanium or the nal titanium hydride in the underlying charge.Under normal operating conditions. the temperature of the top orabsorbing layer is suiliciently high to cause all or most of thedistilled excess calcium to react with the titanium dioxide to formcalcium oxide and reduce some of the titanium dioxide. If any of thedistilled excess calcium should condenseas such in the top or absorbinglayer, it would react with the hydrogen gas admitted to hydride thereduced titanium, to form calcium hydride; which would, of course, beadmixed with the calcium oxide and titanium dioxide in the top orabsorbing layer. In any event, it does not contaminate the reducedtitanium then initially present in the underlying charge or the titaniumhydride finally present in the underlying charge. In other words,titanium hydride of high purity may be formed conveniently in thepractice of the invention. The titanium hydride in the underlying chargeis separately recovered in any suitable manner. For example, the chargeis preferably crushed. after which the calcium oxide may be eliminatedby leaching the charge with a suitable solvent, such as a dilute acid,for example hvdrochloria, sulfuric, or acetic acid, or a solution ofammonium salt. 'Ihe free titanium hydride may then be suitably treatedto lplace it in marketable form, such as bars or powder.

While in` the exampledescribed, calcium hydride is the reducing metalcompound employed, other reducing agents can be employed, such as thehydrides of other alkaline earth metals. The oxide of any of thealkalineearth metals, formed as a result of the reducing reaction, may besimilarly eliminated from the resulting underlying charge by leaching.

It will be clear to those skilled in this art that the method of theinvention lends itself to a number of useful modifications and that theabovedescribed practiceis lonly by 'way of illustration,

1. In the productionof titanium hydride, the improvement which comprisesgradually heating a charge of titanium compound and alkaline earth metalhydride in a reaction zone to a temperature suiliciently hightodissociate the alkaline earth metal hydride into alkaline earth metaland hydrogen gas and to reduce the titanium compound with the alkalineearth metal thus reelased to form metallic titanium and a compound ofthe alkaline earth metal, the alkaline earth metal hy-'- dride beingpresent in amount sufllcient to yield on dissociation the reducingalkaline earth met-al in excess of the amount required to effectreduction of the titanium compound, evacuating the reaction zone whileat a temperature suiliciently high to dissociate the excess alkalineearth metal hydride toremove hydrogen gas and gaseous products ofreaction therefromgand to distill and pass the excessalkaline earthmetal thus released from the charge into' a body of absorbing material,introducing hydrogen gas into the heated reaction zone in amountsufficient to convert the reduced titanium to titanium hydride, coolingthe resulting charge containing the titanium hydride and compound of thealkaline earth metal, and separately recovering the titanium hydride byleaching the charge with a solvent for the compound of the alkalineearth metal.

2. In the production of titanium hydride, the improvement whichcomprises gradually heating a charge of titanium compound and alkalineearth metal hydride in a reaction zone containing an inert gas in amountto place the reaction zone under substantial positive pressure to atemperature suiciently high to dissociate the alkaline earth metalhydride into alkaline earth metal and hydrogen gas and to reduce thetitanium compound with the alkaline earth metal thus released to formmetallic titaniumv and a compound of the alkaline earth metal, thealkaline earth metal hydride being present in amount suicient to yieldon dissociation the reducing alkaline earth metal in excess of theamount required to effect reduction of the titanium dioxide, evacuatingthe reaction zone while at a temperature sufficiently high to dissociatethe excess alkaline earth metal hydride to remove hydrogen gas, theinert gas and gaseous products of reaction therefrom and to distill andpass the excess alkaline earth metal thus released from the charge intoa body of absorbing material, introducing hydrogen gas into the heatedreaction zone in amount sufcient to convert the reduced titanium totitanium hydride, cooling the resulting charge containing the titaniumhydride and compound of the alkaline earth metal, and separatelyrecovering the titanium hydride by leaching the charge with a solventfor the compound of the alkaline earth metal.

3. In the production of titanium hydride, the

Ato a; temperature sumcie'utiyfmgnto dissociate the alkaline earth metalhydride into alkaline earth metal and hydrogen'gasfandto reduce thetitanium dioxide pigment with the-alkaline earth metal thus released toform' metallic titanium and an oxide of the alkaline earth metal, thealkaline -earth metal hydride being present in amount lsuillcient toyield on dissociation the reducing and to distill and pass the excessalkaline'earth metal thus Vreleased from the charge into an absorbingbody of titanium dioxide pigment, in-

troducing hydrogen gas into the heated reaction Aalkaline earth metalhydride into alkaline earth metal and hydrogen gas `and to reduce thetitanium dioxide pigment with the alkaline earth metal thus released toform metallic titanium and an oxide of the alkaline earth metal, thealkaline earth metal hydride being present in amount sufficient to yieldon dissociation the reducing alkaline earth metal in excess of theamount required to eiect reduction of the titanium dioxide, evacuatingthe reaction zone while at a temperature sumciently high to dissociatethe excess` alkaline earth metal hydride to remove hydrogen gas andgaseous products of reaction therefrom and to distill and pass theexcess alkaline earth metal thus released from .the charge into anabsorbing body of zirconium dioxide pigment, introducing hydrogen gasinto the heated reaction zone in amount suilicient to convert thereduced titanium to titanium hydride, cooling the resulting chargecontaining the titanium hydride and the oxide of the alkaline earthmetal, and separately recovering the titanium hydride by leaching thecharge with a solvent for the oxide of the alkaline earth metal. f

5. In the production of titanium hydride, the improvement which`comprises gradually heating a charge of titanium dioxide pigment andalkaline earth metal hydride in a reaction zone `to a temperaturesufficiently high to vdissociate the alkaline earth metal hydride intoalkaline earth metal and hydrogen gas and to `reduce the titaniumdioxide pigment with the alkaline earth metal thus released to formmetallic titanium and an oxide of the alkaline earth metal, the alkalineearth metal hydride being present in amount suftlcient to yield ondissociation the reducing alkaline earth metal in excess of vthe amountrequired to effect reduction of the titanium dioxide, evacuating thereaction zone while at a temperature suiliciently high to dissociate theexcess alkaline earth metal hydride. to remove hydrogen gas and gaseousproducts. of reaction therefrom and to distill and pass the excessalkaline earth metal thus released from the charge into an absorbingbody of chromium oxide pigment, introducing hydrogen gas into the"heated reaction zone in vamount sufilcient to convert the reducedtitanium to titanium hydride; cooling the resulting charge `containingthe titanium hydride 'and the oxide of the alkaline earth metal, andseparately recovering the titaniuml hydride by leachingthe charge withasolvent for thevoxide of the alkaline earth metal.

6. In the production ozfv titanium hydride,the improvement whichcomprises placing a charge of titanium `dioxide pigment 'and -alkalineearth metal hydride ina reaction zone, placing a layer of absorbingmaterial on top of the charge; gradually heating the charge toatemperature suf- `flciently high to7 dissociate` the alkaline earthmetal hydride into alkaline earth metal and `hyi ciate the excessalkaline earth metal hydride to remove hydrogen gas and gaseous productsoi' reaction therefrom and to distill and pass the excess alkaline earthmetal thus released from the underlying charge into the overlying layerof absorbing material, introducing hydrogen gas into the heated reactionzone in amount sufllcient to convert the reduced titanium to titaniumhydride, cooling the resulting charge containing the titanium hydrideand the oxide of the alkaline earth metal, separating the overlyinglayer of absorbing material from the underlying charge, and separatelyrecovering the titanium hydride by leaching the charge with a solventfor the oxide of the alkaline earth metal. i

'7. In the production of titanium hydride, the

improvement which lcomprises placing a charge foi' titanium dioxideEpigment and alkaline? 'earth metal lhydride in' "afreaction-4 zone,placing' an 'absorbing layer of titanium'dioxidc'epigment on top of thechargagradually' heating 'the chargetoa temperature suflicientlyhigh-gradually to dissociate thealkaline earth'metal4 hydride intoalkaline earth metal 'andhydro'gengas to reduce-the titanium dioxide inthe charge' with the alkaline earth vmetalthus released to form metallictitanium' and an oxide 'of the'alkaline earth-metal, the alkaline earthmetal hydride being present ln amountsufilcient to yieldon dissociationthe reducing alkaline earth metal in `excess of the amount requiredto'eiect reduction of the titanium dioxide, evacuating the reaction zonewhile at a temperature suiliciently highto Vdissociate the excessalkaline earth metal hydride to remove hydrogen gas andA gaseousproducts of reaction therefrom and to distill and pass the excessalkaline earth metal thus released from the underlying charge into theoverlyinglayerof titanium dioxide pigment, introducing hydrogen gas intothe heated reaction zone in amount suflicient to convert the reducedtitanium to titanium hydride,

cooling the resulting charge containing the titanium hydride and theoxide of the alkaline earth metal, separating the overlying layer ofabsorbing material from the underlying charge, and separately recoveringthe titanium hydride .by leaching the charge with a solvent for theoxide of the alkaline earth metal.

improvement which comprises placing a charge s of titanium dioxidepigment and alkaline earth metal hydride in a reaction zone, placing alayer of absorbing material on top of the charge, gradually heating thecharge in the presence of an inert gas maintained under substantialpositive pressure to a temperature suiiiciently high to dissociate thealkaline earth metal hydride into alkaline earth metal and hydrogen gasto reduce the titanium dioxide with the alkaline earth metal thusreleased to vform metallic titanium and an oxide of the alkaline `earthmetal, the alkaline earth metal hydride being present in amountsufficient to yield on dissociation the reducing alkaline earth metal inexcess of the amount required to elect reduction of the titaniumdioxide, evacuating the reaction zone while at a temperaturesufliciently high to dissociate the excess alkaline earth metal hydrideto remove hydrogen gas, the inert gas and gaseous'products of reactiontherefrom ami to'distill and pass the excess alkaline earth metal thusreleased from the underlying charge into the overlying layer ofabsorbing Inaterial, introducing hydrogen gas into the heated reactionzone in amount suflcient to convert the reduced titaniumto titaniumhydride, cooling the resulting charge containing the titanium hydrideand the oxide of the alkaline earth metal, separating the overlyinglayer of absorbing material from the underlying charge, and separatelyrecovering the titanium hydride by leaching the charge with a `solventfor the oxide of the alkaline earth metal. I v i 8. In the production oftitanium hydride, the

9. In the production of titanium hydride, the improvement whichcomprises placing a, charge of titanium dioxide pigment and calciumhydride in a reaction zone, placing'a layer of absorbing material on topof the charge, gradually heating the charge to a temperaturesufliciently high gradually to dissociate the calcium hydride intocalcium and hydrogen gas to reduce the titanium dioxide in the chargewith the calcium thus released to form metallic titanium and calciumoxide, the calcium hydride being present in amount suflicient to yieldon dissociation reducing calcium metal in excess of the amount requiredto eiect reduction of the titanium dioxide, evacuating the reaction zonewhile at a temperature suiliciently high to dissociate the excesscalcium hydride to remove hydrogen gas and gaseous products of reactiontherefrom and to distilland pass the excess calcium thus released fromthe underlying charge into the overlying layer of absorbing material,introducing hydrogen gas into the heated reaction zone in 'amountsuliicient to convert the reduced titanium to titanium hydride, coolingthe resulting charge containing the titanium hydride and the calciumoxide, separating the overlying layer of absorbing material from theunderlying charge, and separately recovering the titanium hydride byleaching the charge with a solvent for the calcium oxide.

10. In the production of titanium hydride, the improvement whichcomprises placinga charge of titanium dioxide pigment and calciumhydride in a reaction zone, placing an absorbing layer of metal oxide ontop ofthe charge, gradually heating the charge toa temperaturesuiiiciently high gradually to dissociate the calcium hydride intocalcium'and hydrogen gas to reduce the titanium dioxide in the chargevwith the calcium thus released to form metallic titanium and calciumvoxide, the calcium hydride being present in amount suiilcient to yieldon dissociation-'reducing calcium metal in excess ofthe amount requiredto effect reduction of the titanium dioxide, evacu- Y 1l atingthereaction zone while at a temperature sumciently high to dissociate theexcess calcium hydride to remove hydrogen gas and gaseous products ofreaction therefrom and to distill and pass the excess calcium thusreleased from the underlying charge into the overlying layer of metaloxo ide, introducing hydrogen gas into the heated reaction zone inamount suillcient to convert the reduced titanium to titanium hydride,cooling the resulting charge containing the titanium hydride and thecalcium oxide, separating the overlying layer of absorbing material fromthe underlying charge, and separately recovering the titanium hydride byleaching the charge with a solvent for the calcium oxide.

11. `In the production of titanium hydride, the improvement whichcomprises placing a charge of titanium dioxide pigment and calciumhydride in a reaction zone, placing an absorbing layer of titaniumdioxide pigment on -top of the charge, gradually heating the charge to atemperature suiciently high gradually to dissociate the `alkaline earthmetal hydride into calcium and hydrogen gasto reduce the titaniumdioxide in the charge with the calcium thus released to form metallictitanium and calcium oxide, the calcium hydride being present in amountsufficient to yield on dissociation reducing calcium metal in excess ofthe amount required to effect reduction of the titanium dioxide,evacuating the reaction zone while at a temperature sufliciently high todissociate the excess calcium hydride to remove hydrogen gas and gaseousproducts of reaction therefrom and to distill and pass theexcess calciumthus released from the underlying charge into the overlying layer oftitanium dioxide pigment, in-

troducing hydrogen gas into the heated reaction zone in amountsufficient to convert the reduced titanium to titanium hydride, coolingthe resulting charge containing the titanium hydride and the calciumoxide, separating the overlying layer of absorbing material from theunderlying charge, and separately recovering the titanium hydride byleaching the charge with a solvent for the calcium oxide.

12. In the production of titanium hydride, the4 improvement whichcomprises placing a charge of titanium dioxide pigment and calciumhydride in a reaction zone, placing an absorbing layer of titaniumdioxide pigment on top of the charge, evacuating the reduction zone toremove air and moisture, gradually heating the charge to a temperaturesuoiently high gradually to dissociate the alkaline earth metal hydrideinto calcium and hydrogen gas to reduce the titanium dioxide in thecharge with the calcium thus released to form metallic titanium andcalcium oxide, the calcium hydride being present in amount suilcient toyield on dissociation reducing calcium metal in excess of the amountrequired to effect reduction of the titanium dioxide, evacuating thereaction zone while at a temperature sufficiently high to dissociate theexcess calcium hydride to remove hydrogen gas and gaseous products ofreaction therefrom and to distill and pass the excess calcium thusreleased from the underlying charge into the overlying layer of titaniumdioxide pigment, introducing hydrogen gas into the heated reaction zonein amount suillcient to convert the reduced titanium to titaniumhydride, cooling the resulting charge containing the titaniumhydride andthe calcium oxide, separating the overlying layer of absorbing materialfrom the underlying charge, and separately recovering the ,v l 12titanium hydride by leaching the charge solvent for the calcium oxide.

13. VIn the production of titanium hydride, the improvement whichcomprises placing a charge of titanium dioxide pigment and calciumhydride with i a in a reaction zone, placing an absorbing layer ofhydride is heated to a temperature sufficientlytitanium dioxide pigmenton top of the charge, evacuating the reaction zone to remove air andmoisture, illling the reaction zone with an inert gas, maintaining thereaction zone under substantial positive pressure with said inert gas,gradually heating the charge to a temperature sumciently high graduallyto dissociate the alkaline earth metal hydride into calcium and hydrogengas to reduce the titanium dioxide in the charge with the calcium -thusreleased to form metallic titanium and calcium oxide, the calciumhydride being present in amount sufllcient to yield on dissociationreducing calcium metal in excess of the amount required to effectreduction of the titanium dioxide, evacuating the reaction zone while ata temperature suiliciently high to dissociate the excess calcium hydrideto remove hydrogen gas, the inert gas and gaseous products 'of reactiontherefrom and to dstill and pass the excess calcium thus released fromthe underlying charge into the overlying layer of titanium dioxidepigment, introducing hydrogen gas into the heated reaction zone inamount sufficient to convert the reduced titanium to titanium hydride,cooling the resulting charge containing the titanium hydride and thecalcium oxide, separating the overlying layer of absorbing material fromthe underlying charge, and separately recovering the titanium hydride byleaching the charge with a solvent for the calcium oxide.

14. In a method wherein a charge comprising a titanium compound and analkaline earth metal high to dissociate the alkaline earth metal hydrideinto alkaline earth metal and hydrogen gas and to reduce the titaniumcompound with the alkaline earth metal thus released to form metallictitanium and a. compound of the alkaline earth metal, the alkaline earthmetal hydride being present in amount suflicient to yield ondissociation the reducing alkaline earth metal in excess of the amountrequired to eiect reduction of said titanium compound, the improvementwhich comprises externallyv heating the charge together with a separateoverlying layer of an absorbing material sufficiently high to reducesaid titanium compound and to distill and pass the excess alkaline earthmetal from the charge into the separate layer of absorbing material,said absorbing material being a metal oxide with which the excessdistilled alkaline earth metal is capable of reacting.

15. In a method wherein a charge comprising a titanium compound and analkaline earth metal Iis heated to a temperature sufficiently hi'gh tore,- duce the titanium compound and form a compound of the alkalineearth. metal, the alkaline earth metal being present in amount in excessof that required to effect reduction of said titanium compound, theimprovement which comprises externally heating the charge together witha separate overlying layer of an absorbing material sufciently high toreduce said titanium compound and to distill and pass the excessalkaline earth metal from the charge into the separate layer ofabsorbing material, said absorbing material being a metal oxide withwhich the alkaline earth metal is capable of reacting.

PETER P. ALEXANDER.

15 lll.

Certicate of Correction Patent No. 2,427,338. September 16, 1947.

. PETER P. ALEXANDER It is hereby certified that errors appear in theprinted specification of the above numbered patent requiring correctionas follows: Column 2, line 25, for totanium read titanium; column 7,line 21, claim 1, for reelased read released; line 57, claim 2, fordioxide read compound; and that the said Letters Patent should be readwith these corrections therein that the same may conform to the recordof the case in the Patent Cflce.

Signed and sealed this 6th day of January, A. D. 1948.

THOMAS F. MURPHY, v

Assistant 'ommssoner of Patents.

